The skin, mucous membrane, hair and/or the nails constitute a physical barrier between an organism and their environment. The skin is composed of two tissues: the epidermis and the dermis. The dermis forms approximately 90% of the thickness of the skin, containing collagen, elastin, several differentiated structures such as blood vessels, sweat glands, and mainly cell-types such as fibroblasts, macrophages and adipocytes.
In the skin, the adipocytes are located in the deepest layers of the dermis, the hypodermis. The adipocytes are organized in lobules, separated by septa of connective tissue that contain vessels, nerves and lymph nodes. The main function of the adipocytes is the storage of fat in vacuoles in the form of triglycerides. In addition to this energy-related function, these cells are also involved in the production of some hormones (estrogen) as well as in the synthesis of molecules implicated in inflammatory response.
One of the disorders related to the adipose cells of the hypodermis that has been highly focused on by the cosmetic industry, is cellulite. Cellulite is the result of an excessive accumulation of lipids in the adipose tissue which puts a considerable amount of pressure on the surrounding epithelial tissue, resulting in an irregular appearance of the skin with the presence of dimples. From an aesthetic point of view this appearance has been named orange peel.
For the treatment of this problem, a number of agents exists that stimulate lipolysis by reducing the volume of accumulated lipids, thus showing a draining effect which reduces the volume by eliminating retained water stored between the tissues. Furthermore, other agents with firming effect in the treatment of cellulite can also be used that correct the irregular appearance of the skin.
The most widely used anti-cellulite agent is caffeine due to its lipolytic effects in adipocytes [Vogelgesang B. et al., “In vitro and in vivo efficacy of sulfo-carrabiose a sugar-based cosmetic INGREDIENTS with anti-cellulite properties”, Int. J. Cosmet. Sci., 2011, 33(2), 120-5; Nakabayashi H. et al., “Inhibitory effects of caffeine and its metabolites on intracellular lipid accumulation in murine 3T3-L1 adipocytes”, Biofactors, 2008, 34(4), 293-302], in addition to its draining effects. Furthermore, a high number of alternative agents also exist that possess similar mechanisms. A recent strategy in the search for new anti-cellulite agents is based on the influence over the actions related to circadian rhythms in the skin, [Dupressoir A. et al., “Characterization of a mammalian gene related to the yeast CCR4 general transcription factor and revealed by transposon insertion”, J. Biol. Chem. 1999, 274(43), 31068-75; Dupressoir A. et al., “Identification of four families of yCCR4- and Mg2+-dependent endonuclease-related proteins in higher eukaryotes, and characterization of orthologs of yCCR4 with a conserved leucine-rich repeat essential for hCAF1/hPOP2 binding”, BMC Genomics, 2001, 2:9; Green C. B. et al., “Loss of Nocturnin, a circadian deadenylase, confers resistance to hepatic steatosis and diet-induced obesity”, Proc. Nat. Acad. Sci. USA, 2007, 104(23), 9888-93] which similar to other tissues, experiences functional variations due to changes between day and night.
In humans, as well as other animal species, a large portion of their social behavior and their physiological functions vary from day to night in a rhythmic fashion. The system that defines the circadian clock comprises central and peripheral components. In mammals, the central component of this oscillatory system resides in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus [Boivin D. B. et al., “Circadian clock genes oscillate in human peripheral blood mononuclear cells”, Blood 2003, December, 102(12), 4143-4145]. This nucleus mainly functions by reception of light signals from specialized retina cells, the retina ganglion cells and activating a series of transcriptional, translational, and posttranslational mechanisms involving several genes, such as CLOCK, BMAL1, PER, and CRY that result in cascades of gene expression with 24 hr periodicity. Green C. B. et al., “The Meter of Metabolism”, Cell, 2008, 134(5), 728-742]. Peripheral tissues and organs also possess autonomous regulatory systems that are independent of the central clock, but use the same machinery of genes and show entrainment to external stimuli that the tissue may be subject to [Kaway M. and Rosen C. J., “PPARγ: a circadian transcription factor in adipogenesis and osteogenesis”, Nat. Rev. Endocrinol., 2010, 6, 629-636].
Some functions that intervene in the regulation of circadian rhythms, or which are subject to them, are the production of hormones, cytokine levels, temperature regulation or glucose levels, amongst others [Mehling A. and Fluhr J. W., “Chronobiology: biological clocks and rhythms of the skin”, Skin Pharmacol. Physiol, 2006, 19(4), 182-9].
Several of the skin's functions are also subject to circadian rhythms, similar to that occurring in other organs. Thus, it has been observed that various parameters investigated in woman, such as blood circulation, amino acid content and Transepidermal Water Loss (TEWL) increase during the night. On the other hand, the production of sebum, measured on the forehead using a sebumeter, gives its highest values around midday. The pH of the skin tends to decrease throughout the night then increase throughout the day. The skin's blood circulation demonstrates circadian rhythms and ranges during the day from low circulation early morning to then increasing, reaching its maximum values in the final hours of the afternoon going on to evening. Interestingly, the circadian rhythms can also be found at cellular level in the skin, as it has been observed that proliferation of epidermal cells demonstrates its highest values at around 11 pm. [Mehling A. and Fluhr J. W., “Chronobiology: biological clocks and rhythms of the skin”, Skin Pharmacol. Physiol, 2006, 19(4), 182-9].
One of the nocturnal functions in which an effect has been observed is that of adipogenesis, as one of the genes studied with such effect is nocturnin. Thus, in some of the first studies carried out with Xenopus laevis retina that aimed to isolate genes affected by circadian rhythms, it was observed that the expression nocturnin mRNA was present at high levels in early night. [Green C. B. and Besharse J. C., “Identification of a novel vertebrate circadian clock-regulated gene encoding the protein Nocturnin”, Proc. Nat. Acad. Sci. USA, 1996, 93(25), 14884-8]. On the other hand, it was later found that in addition to being expressed in the retina in rats, nocturnin mRNA was expressed in numerous tissues, such as the liver, brain, lung, heart, ovary, skeletal muscle, testicles and bone marrow. Similarly, it was observed that a great circadian variation existed in the expression of nocturnin mRNA, with its maximum levels occurring at the beginning of the night [Dupressoir A. et al., “Characterization of a mammalian gene related to the yeast CCR4 general transcription factor and revealed by transposon insertion”, J. Biol. Chem. 1999, 274(43), 31068-75; Dupressoir A. et al., “Identification of four families of yCCR4- and Mg2+-dependent endonuclease-related proteins in higher eukaryotes, and characterization of orthologs of yCCR4 with a conserved leucine-rich repeat essential for hCAF1/hPOP2 binding”, BMC Genomics, 2001, 2:9].
Regarding the function of nocturnin, studies with knock out mice that are unable to express nocturnin demonstrated that, even though these individuals showed normal general circadian behavior, they presented resistance to diet-induced obesity and they also showed other metabolic changes such as a lower accumulation of lipids in the liver. Therefore, this metabolic phenotype suggests that nocturnin controls specific secondary circadian channels associated with the accumulation and use of lipids. [Green C. B. et al., “Loss of Nocturnin, a circadian deadenylase, confers resistance to hepatic steatosis and diet-induced obesity”, Proc. Nat. Acad. Sci. USA, 2007, 104(23), 9888-93]. Another one of the functions in which nocturnin's involvement has been observed is inflammation. Nocturnin stabilizes the pro-inflammatory transcript iNOS and a reduction in nocturnin would mean a reduction in inflammation. [Niu S. et al., “The circadian deadenylase Nocturnin is necessary for stabilization of the iNOS mRNA in mice” PloS one 2011, 6(11), e26954].
As nocturnin is a marker that is correlated with the accumulation and use of lipids, it may be used as a base for further studies to identify stimulation or reduction activity on the accumulation of lipids in adipocytes in the dermis and in the treatment of inflammation.
Surprisingly, the applicant of this invention has found an exopolysaccharide of bacterial origin that is an alternative to the problems in the state of the art previously mentioned regarding the accumulation of lipids, cellulite, inflammation or lipolysis, amongst others.